I've just had a random thought. Let's say that you hold a growing animosity towards someone. This hate, anger, and/or disgusted grows daily. In time these's thoughts become so strong that you end up doing something physical. Now that's one means of expressing you feelings. My question what if you create an embodiment for those feelings? A thought-demon. Something that you can summon up (mentally) and use as a psychic attack dog whenever this person bothers you. It would be similar to a servitor but not quite. More like a personal demon that does your will, an embodiment of those feeling, for lack of a better term a thought-form.